The Lunar Terminator Visualization Tool (LTVT) is a free software tool for the intermediate to advanced student of lunar topography. It permits Moon images in a variety of formats to be located, viewed and compared with a uniform set of tools. It also permits highly accurate measurements to be made on those images.
Design Goals
Accuracy
Configurable and expandable by end user
Ease of use
Features
Displays orthographic views of the Moon from any user-selected angle
Can paint the lunar sphere with a variety of user-supplied imagery:
Texture files covering the whole, or a part of, the Moon in simple cylindrical projection
Maps in Mercator (e.g., equatorial LAC's), Transverse Mercator (e.g., LTO's) and Lambert (e.g., high latitude LAC's)
Any actual photo taken from Earth or space, provided the date, time and camera location are known
With optional digital elevation model (DEM) data, can paint the sphere with simulations of the expected pattern of light and shadow for any combination of viewing and lighting angles; including correct projection of the three-dimensional locations of the surface objects.
On the painted sphere, can overlay on the dots encoding information specific to particular longitudes and latitudes, including:
Nomenclature
Point elevations
Features of special interest
Dot files available for complete current IAU nomenclature and major selenodetic control systems.
Accurately plots the theoretical terminator position based on a user-supplied sub-solar point.
Interactively displays the sun angle as the mouse is moved over the image.
Can accurately compute the viewing and lighting geometry for any date from 1601-xxxx using optional JPL ephemeris files.
Infinite zoom capability
An unlimited number of instances of the program can be run simultaneously for overlay of images from different sources (similar to Photoshop "layers")
Using the optional JPL ephemeris files, can predict past or future times when the terminator will be at a particular location relative to the surface features, based either on solar colongitude or on the sun angle at a particular feature.
Can similarly tabulate past and future times when a given surface feature will be seen at a given distance from the disk center (due to varying librations).
List of calibrated photos permanently stored on disk. List can be interrogated to automatically locate and display all calibrated photos showing a particular feature, ranked by sun angle.
Can also search a list of dates and times of uncalibrated photos to locate ones that could potentially show a given feature with a particular lighting (if it happens to fall with the photo's field).
Tools for:
Altering Gamma of displayed texture/image.
Identifying nearest feature in current dot file.
Measuring distances and bearings in kilometers and degrees.
Determining surface height differences based on the observed starting and ending points of solar shadows.
Determining expected limit of visibility (theoretical limb circle) for a given sub-Earth point.
Interactively drawing circles for accurately estimating (and optionally recording) the positions and diameters of circular features.
Counting number of displayed dots.
Saving annotated version of current screen display.
System Requirements
LTVT works only on Windows-compatible PC's
It displays best using the "Windows Classic" desktop theme (simple window borders)
Lunar Terminator Visualization Tool
Table of Contents
Description
The Lunar Terminator Visualization Tool (LTVT) is a free software tool for the intermediate to advanced student of lunar topography. It permits Moon images in a variety of formats to be located, viewed and compared with a uniform set of tools. It also permits highly accurate measurements to be made on those images.Design Goals
Features
System Requirements
Additional Information
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